edit:Looks like the version from stretch works https://packages.debian.org/stretch/font-manager Tried in a Kubuntu 16.04 VM, newer versions run into unmet dependencies.
Very different interface, not compatible with the earlier version so try first. Do not need to use the font manager once all those foreign fonts are disabled. Might not bother upgrading.

Thank you so much. That worked like a charm. I deleted my font cache, all files to recycle bin in case there was a problem. And the second load and after a restart, third load of gimp was only a few seconds.

Interesting thing is, Firefox is fast again. And certain websites that always seemed to almost lock the system, they are fast too. Huh. I'd been trying all kinds of advice over the last few years to speed firefox up. Even dropped some plugins and it might have been the font cache the whole time.

If GIMP is looking for its own files it should already know where to find them.
Here it seems GIMP is looking in all the trash cans of the neighborhood in search for usable files
without caring what app they belong to. That's what the people who look in trash cans usually do
and why would GIMP want to be such a citizen ? Why can't it be equipped with a reasonable
set of assets to begin with ?

(02-06-2018, 12:11 PM)gunnar-gimp Wrote: If GIMP is looking for its own files it should already know where to find them. Here it seems GIMP is looking in all the trash cans of the neighborhood in search for usable files without caring what app they belong to. That's what the people who look in trash cans usually do and why would GIMP want to be such a citizen ?

Gimp (or more accurately, the GTK support library it uses) isn't looking for files everywhere. It is just converting the fonts installed system-wide into something it can use. Yes, it takes time, but it should happen only once.

(02-06-2018, 12:11 PM)gunnar-gimp Wrote: Why can't it be equipped with a reasonableset of assets to begin with ?

Even if Gimp came with its own set of fonts, people would want to use the fonts they use in other tools.